Lubricating oil composition



LUBRICATING OIL COMPOSITION Andrew D. Abbott, Ross, Calif., assignor toCalifornia Research Corporation, San Francisco, Calif., a corporation ofDelaware No Drawing. Filed Mar. 31, 1958, Ser. No. 724,871

6 Claims. (Cl. 252-32.7)

This invention relates to a lubricating oil composition having improvedphysical properties. More particularly the invention is concerned with astable viscosity mineral lubricating oil composition containing metalsalt organic detergent additives in combination with polymericthickening additives.

Polymeric additives are extensively used in mineral lubricating oilcompositions to impart desirable viscositytemperature characteristics tothe compositions. These additives are designed to modify lubricatingoils so that changes in viscosity occurring with variations intemperature arekept as small as possible. Lubricating oils containingsuch polymeric additives are somewhat thickened at the highertemperatures normally encountered in engine operation while at the sametime retaining desirable low viscosity fluidity at' cold startingtemperatures. The ability of a lubricating oil to accommodate increasedtemperatures with a minimum decrease in viscosity is indicated by itshigh viscosity index as derived from commonly accepted viscositystandards. Because of the aforementioned properties, these polymericadditives have been conveniently termed both thickeners and viscosityindex improvers.

Polymers of alkyl methacrylates are particularly effective additives ofthe above type. Included are polyalkyl methacrylates. in which the alkylgroups are mixtures of lower alkyl groups of 7 carbon atoms or less andhigher alkyl groups of 8 carbon atoms or more. Some of the moreimportant polymeric methacrylates also provide enhanced detergentproperties to mineral lubricating oil compositions as Well as desirableviscosity-temperature characteristics. Among the more importantpolymeric viscosity index improvers and detergents of this type are thecopolymers of the aforementioned alkyl methacrylates with monomerscontaining polar groups such as the N,N dialkylaminoalkylmethacrylates,the polyglycolmonomethacrylates and the vinyl nitrogen heterocycles.

Mineral lubricating oils containing polymeric additives as describedabove are also commonly compounded with metal salt organic detergentadditives. These metal salt additives alleviate the formation ofundesirable engine deposits, by giving the oil enhanced ability tomaintain deposit-forming materials such as sludge and resins fromoxidation in dispersion in the oil. Among the more important additivesof this type are the essentially neutral alkaline earth metal petroleumsulfonates and the alkaline ear metal phenates of their sulfurizedderivatives. Another important type of metal salt organic detergentadditive, namely the zinc dithiophosphates imparts not only detergentcharacteristics but also oxidation and corrosion inhibiting propertiesto mineral lubricating oil compositions.

The two different classes of additives described above have beencombined to give mineral lubricating oil com positions having excellentdetergent properties along with superior viscosity-temperaturecharacteristics. Unfortu-' nately, it happens that the addition of theimportant metal salt organic detergents to mineral lubricating oilscontaining the polymeric thickeners mentioned above has a decidedlyadverse effect on the viscosity-temperature characteristics of themineral lubricating oil compositions.

' ranges commonly encountered in internal combustion en gines. Polymericthickener-s of the important polymethacrylate ester type are added tothese oils to raise the viscosity index radically and thus enable asingle oil to meet the specification viscosity ranges of two or threedifferent SAE viscosity grades. The increase in viscosity, particularlyat low temperatures where only certain viscosities can be tolerated, andthe depreciation of the aforementioned critical viscosity indeximprovement of the thickened lubricating oil by the addition of the moreimportant metal salt organic detergent additives referred to above mayprevent an oil from qualifying as a .multigrade oil. a g I The additionof the metal salt organic detergent additives to the thickened minerallubricating oils has both an immediate adverse effect as describedabove, an d also a postponed effect in that further undesirableincreases in viscosity and depreciation of the viscosity index areobserved over certain periods of time. This effect which has beenconveniently termed viscosity drift is extremely critical since anotherwise satisfactory oil may become completely unsatisfactory duringthe usual storage periods for lubricating oils.

It has now been found that stable viscosity-temperature characteristicsare'provided in mineral lubricating oil compositions comprising a major"portion ofa mineral lubricating oil, a minor portion suificient toimprove the viscosity index of the mineral lubricating oil of analkylmethacrylate polymer, a minor portion sufiicient to enhance thedetergent characteristics of the mineral lubricating oil of a metal saltorganic detergent additive selected from the class consisting of neutralalkaline earth metal petroleum sulfonate, alkaline earth metal phenate;

sulfurized alkaline earth metal phenate and zinc aromaticdithiophosphate and a minor portion sufficient to stabilize I theviscosityof the mineral lubricating oil composition of an alkanediolcontaining from 4 to 8 c'arbonatoms.

The mineral lubricating oil compositions of the invention possessunusually stable viscosity-temperature char-v acteristics compared tomineral lubricating oil,composi-'- tions containing polymethacrylateester viscos'it'yinde'xd improvers in combination with metal saltorganic detergent additives without the alkanediol. Particularly in thecase of the multigrade lubricating oils where certain minimum lowtemperature'viscosities and minimum variations in viscosty of the oilover broad temperature ranges are critical, the outstanding propertiesof} the Y compositions according to the invention are mo stappreciated.

tically unchanged, even over extended periods'of time.

The alkanediols containing from 4 to 8 carbon'ator'ns pounds include1,4-butanediol, Z-methyI-ZA- en'tanediQl f It is found that theviscosity as well as the 'viscosity index of the present compositionsremains pra' c-r and 2-ethyl-l,3-hexanediol. For present purposes the 2-methyl-2-4-pentanediol is preferred since it provides the most viscositystable compositions at lowest concentration. The metal salt organicdetergent additives of the more important types such as are employed inthe mineral lubricating oil compositions according to the presentinvention include the neutral alkaline earth metal petroleum sulfonates,alkaline earth metal phenates, sulfurized alkaline earth metal phenatesand zinc aromatic dithiophosphates as mentioned above. These particularmetallo organic additives are generally recognized as effectivelubricating oil detergents and inhibitors and should require noparticular description here. Illustrative alkaline earth metal petroleumsulfonates include barium petroleum sulfonate, calcium petroleumsulfonate, magnesium petroleum sulfonate and slightly basic calciumpetroleum sulfonates having a base ratio not greater than 0.6 (baseratio" being the ratio of basic calcium to total calcium). seem to havean adverse effect on the thickened mineral lubricating oils. Suitablealkaline earth metal alkyl phenates and sulfurized alkaline earth metalalkyl phenates include calcium cetylphenate, calcium tetradecylphenate,barium cetylphenate, and sulfurized calcium cetylphenate. Theaforementioned phenates preferably contain from to carbon atoms in thealkyl group and may be normal or basic in nature since both types alterthe viscosity-temperature characteristics of the thickened oilsundesirably. The zinc aromatic dithiophosphates of the compositions ofthe invention are characterized by the presence of at least one arylgroup. Illustrative thiophosphates of this type include zinc dodecylphenyl thiophosphate, zinc dihexylphenyl dithiophosphate, zinc hexylnaphthyl dithionhosphate and zinc diamylphenyl dithiophosphate.Thiophosphates without aryl groups do not appear to affect the criticalviscosity properties of the thickened compositions.

The polymeric methacrylate ester lubricating oil thickeners of thecompositions according to the invention are also a recognized class ofeffective lubricating oil additives. In general, they are polymers ofhigher alkyl esters of a,fl-unsaturated monocarboxylic acids of from 3to 8 carbon atoms which contain oil-solubilizing alkyl groups of atleast 8 carbon atoms. Illustrative esters of these types include dodecylmethacrylate, octadecyl methacrylate, tridecylacrylate and tetradecylcrotonate. The methacrylates are presently preferred since they providevery satisfactory improvement in the viscosity indexes of lubricatingoil compositions. Other monomers, including lower alkyl methacrylatessuch as butyl methacrylate, may also be copolymerized with theaforementioned higher alkyl methacrylates. Polar monomers such as thosecharacteristic of polymeric detergent additives for lubricating oils mayalso be included. These polymeric additives are also eiiective viscosityindex improvers as well as superior detergents. The more suitable polarmonomers are the N,N-dialkylaminoalkyl methacrylates such asN,N-diethylaminoethyl methacrylate, the vinyl nitrogen heterocyliccompounds such as vinyl pyridine and vinyl pyrrolidone and thepolyglycol monomethacrylates such as the dodecyl ether ofoctadecaethyleneglycol monomethacrylate.

Polymeric methacrylate viscosity index improvers of the above-mentionedtypes are generally characterized by molecular weights in the range of100,000 to 300,000 and higher. In the case of the detergent polymericcom pounds, the polar monomers are ordinarily present in proportions offrom about 0.1 to about 35.0% by weight of the polymer.

The mineral lubricating oil of the lubricant composition of theinvention may be any of the usual types of mineral lubricating baseoils. Parafiinic or naphthenic base stocks are suitable. The minerallubricating base oils may be refined by any of the conventional methodsOnly the substantially neutral sulfonates such as solvent refining orsulfuric acid refining. Solvent-refined Mid-Continent parafiinic-typebase stocks appear to present the greatest viscosity stability problemand, therefore, have particular application to the compositions of theinvention.

Further illustrations of the improved mineral lubricating oilcompositions according to the present invention are provided by thefollowing examples. Unless otherwise specified, the proportions in theexamples are on a weight basis.

Several mineral lubricating oil compositions containing the typicalpolymethacrylate thickeners referred to above and the metal salt organicdetergent additives were prepared to show the effect of the metal saltadditives on the thickened mineral lubricating oil compositions. In thecompositions the base oil was a Mid-Continent parafiinic 200 neutralsolvent refined mineral lubricating oil having a viscosity of 200 SSU atF. The oil was thickened with 6% by weight of the copolymer of a mixtureof dodecyl methacrylate, octadecyl methacrylate, butylacrylate andN-vinylpyrrolidone in which there are approximately 65 parts by weightof the dodecyl and octadecyl methacrylates, approximately 25 parts byweight of butylacrylate and approximately 10 parts by weight ofN-vinylpyrrolidone. The copolymer has an average molecular weight ofapproximately 150,000 to 200,000. Various metal salt detergent additivesare added to the thickened mineral lubricating oil and the etfect on theviscosity of the oil in Saybolt Seconds Universal (SSU) at 210 F. isobserved as indicated in the following table. The proportions of themetallic salt detergent additives are given in millimoles per kilogram(mM./kg.).

TABLE I Viscosity Viscosity Oil at 210 F., Increase,

SSU SSU,210F.

Thic ened Oil 63.0 Thickened Oil plus 25 mMJkg. calcium sulfonate (baseratio 0.4) 76. 0 13.0 Thickened Oil plus 35 miNL/kg. sulfurized 021- vclum tetradecyl phenate 1 80. 0 17.0 Thickened Oil plus 30 mMJkz. zincdi(tetradecylphenyll dithiophosphate 70.0 7.0 Thiclrcned Oil plus 25mMJkg. zinc butylhexyl dithiophosphate 63.0 0.0

l 'Ietradecyl phenate derived from a. mixture of propylene tetramer andpenta'ner alkylated phenols having an average of approximately 1-1carbon atoms in the alkyl group.

According to the above test results, it will be seen that the importantmetallic salt detergent additives of the alkaline earth metal petroleumsulfonate, alkaline earth metal phenate and zinc aromaticdithiophosphate types all have an adverse effect on the viscosity of thethickened mineral lubricating oil. The unusual nature of the viscositystability problem shown by'the above test data is emphasized by the factthat certain other metal salt detergent additives such as the zincdialkyl dithiophosphates do not have any such adverse effect on theviscosity of the thickened mineral lubricating oil.

The effect of the inclusion of an alkanediol containing from 4 to 8carbon atoms in the thickened mineral lubricating oil compositionscontaining metal salt detergent additives in accordance with thisinvention is shown by a number of examples. Test results illustratingthe viscosity-temperature characteristics of these examples are given inthe following table.

Oil A in the table is the thickened oil described above consisting of a200 neutral solvent-refined mineral lubricating oil containing 6% byweight of methacrylate and vinylpyrrolidone copolymer.

Oil B is the thickened oil plus 25 mM./kg. of calcium petroleumsulfonate (base ratio 0.4) having an average molecular Weight ofapproximately 500.

Oil C is the thickened oil containing 35 rnM./kg of I mM./kg. of calciumpetroleum sulfonate (base ratio 0.4), 6.5 mM./kg. sulfurized calciumtetradecyl phenate and mM./kg. zinc butyl hexyl dithiophosphate.

Oil F is a thickened oil consisting of a 150 neutral solvent-refinedmineral lubricating oil containing 7.1% by weight of the copolymericthickener described. above.

Oil G is the immediately preceding thickened oil containing 28 mM./ kg.of calcium petroleum sulfonate (base ratio 0.4) having an averagemolecular weight of approximately 500, 6.5 mM./kg. sulfurized calciumtetradecyl phenate and 10 mM./kg.-zinc butyl hexyl dithiophosphate.

Oil H is a thickened oil consisting of 50% by weight 100 neutralsolvent-refined mineral lubricating oil and 50% by weight 200 neutralsolvent-refined mineral lubricating oil containing 5.0% by weight of thecopolymer of butyl and dodecyl methacrylates having a molecular weightof approximately 250,000.

Oil I is the thickened oil immediately preceding containing 35 mM./kg.of calcium petroleum sulfonate (base ratio 0.4) having an averagemolecular weight of approximately 500, 30 mM./kg. sulfurized calciumtetradecyl phenate, l0 mM./kg. Zinc butyl hexyl dithiophosphate and 7ppm. Dow Corning silicone fluid DC 200, a commercial foam inhibitor.

with varying amounts of Z-methyl-Z,4-p'entanediol. The

results of these tests are given in Table III as follows:

TABLE III Days storage at Per Cent 0 0.1% 0.3 Room Tempera- Alkanedioltnre SSU, 210 F 63. 9 61. 7 60. 4 0 SSU, 0 F 5, 300 VI 150 SSU, 210 F00. 4; 7 SSU, 0 F 5, 600

VI 149 SSU, 2l0 F 00.3 14; SSU, 0 F 5,700 .I 149 SSU, 210 F 60. 4 a0 SD,5, 600 I 149 From the above test results it is seen that the minerallubricating oil compositions containing polymeric thickener and metalsalt have unstableviscosity-temperature characteristics during storage.The viscosities at 0v F. are undesirably high to begin with and becomedrastically worse with time. Furthermore, the viscosity index of suchoils deteriorates with time.

By way of contrast, the same mineral lubricating oil compositions with2-rnethyl-2,4-pentanediol have considerably improved low viscosities at0 F. Their viscosity indexes are raised substantially. Both lowtemperature viscosity and the viscosity indexes of such compositions arestable throughout the extended period of 30 days" storage time.

In the foregoing description of the mineral lubricating TABLE II Viscoity Viscosity Viscosity Viscosity Percent Oil at 0 F., at 210 F.,Increase, Correction, Improve- SSU SSU 0 F., 210 F., ment SSU SSU'A-(Thickeued Oil) 7, 800 63.0 B('Ihickeuel Oil Metal Salt) 13,000 76.013.0 B(Ihickened Oil Metal Salt) 0.3%

z-Ethyl lfi-llexanediol 10, 600 68. 0 8. 0 62 o-(Thic'ze-iei Oil MetalSalt) 14, 500 80.0 17.0 C-(Thickeaed Oil Metal Salt) 3% 2Ethyl-l,3-Hexanediol 12,000 70. 0 10. 0 D('Ihickenefl Oil) 4, 900 55. 2E-(Thickeneil Oil Metal Salt) 9, 900 62.3 7. 1 E-(Thickeue'.l Oil MetalSalt) 0.2%

2-Methyl-2,4-Pentanediol 9, 300 59. 2 3. 1 43 E-(Thicke' ei Oil MetalSalt) yl g F-(Thickeaerl 0il) G-(Tbickeued Oil Metal Salt) G(ThickeneclOil Metal Salt 0.1%

2-MetbyL2A-Pentanediol G(Thie r-ened Oil Metal Salt) 0.3%

2-Methyl-2A-Pe'1tanedlol G-(Thickene'l Oil Meta] Salt)2-Ethyl-1,3Hexanedl0l G-(Thickenefl Oil Metal Salt) -l- 0.5%

2-Ethyl-l,3-Hexanediol G(Thicke'1e:l Oil Metal Salt) 0.2%

Negative Dlbntylether Diethylcueglycol 10,000 H-(Thiclrenerl Oil)I-(Thicrenei Oil Metal Salt) 10, 700 I-(Thicreuel Oil Metal Salt) 0.3%

2-Methyl-2,4-Pentanediol 8, 700

In the above-described test results addition of alkanediol to thelubricating oil compositions is shown to overcome practically all theadverse effect on the viscosity incurred by the addition of the metalsalt to the thickened oil. The alkanediols of from 4 to 8 carbon atomsare surprisingly better than other glycols in their improving abilitywhile 2-methyl-2,4-pentanediol is the best.

Experiments were also carried out with the mineral lubricating oilcompositions of the invention to illustrate the stability of theirdesirable viscosity-temperature characteristics over extended periods oftime such as those encountered under normal storage conditions. A numberof samples of thickened oils and metal salts, as described in connectionwith oil G above, were treated be apparent to those skilled in the art.Expressed in numerical ranges, however, the polymeric thickeningadditives will be in the customary range of from 0.1 to

The metal salt f 10.0% by weight of the composition. will be, expressedin mM./kg., in the range of ,5 to

mM./kg. The alkanediol will be present in amountslin the range of from0.05 to 1.0% by weight of the composition.

I claim:

1. A mineral lubricating oil composition comprising a major portion of amineral lubricating oil, from 0.1 to 10.0% by weight of an oil-solublecopolymer of (A) an ester selected from the group consisting ofalkylacrylates and alkylmethacrylates having alkyl groups containingfrom 4 to 6 carbon atoms each, (B) an ester selected from the groupconsisting of alkylacrylates and alkylmethacrylates having alkyl groupscontaining from 12 to 20 carbon atoms each and (C) vinyl pyrrolidone,said copolymer having a molecular weight in the range of 100,000 to300,000 and said vinyl pyrrolidone being from about 0.1 to about 35.0%by weight of the copolymer, from 5 to 100 millimoles per kilogram of ametal salt organic detergent additive selected from the class consistingof neutral alkaline earth metal petroleum sulfonate, alkaline earthmetal phenate, sulfurized alkaline earth metal phenate andzinc aromaticdithiophosphate in which the aromatic groups are selected from the classconsisting of alkyl phenyl and alkyl naphthyl groups and from 0.05 to1.0% by weight of alkanediol containing from 4 to 8 carbon atoms.

2. A mineral lubricating oil composition comprising a major portion of amineral lubricating oil, from 0.1 to 10.0% by weight of a copolymer of(A) an ester selected from the group consisting of alkylacrylates andalkylmethacrylates having alkyl groups containing from 4 to 6 carbonatoms each, (B) an ester selected from the group consisting ofalkylacrylates and alkylmethacrylates having alkyl groups containingfrom 12 to 20 carbon atoms each and (C) vinyl pyrrolidone, saidcopolymer having a molecular Weight in the range of 100,000 to 300,000and said vinyl pyrrolidone being from about 0.1 to about 35.0% by weightof the copolymer, from 5 to 100 millimoles per kilogram each of neutralalkaline earth metal petroleum sulfonate, sulfurized alkaline earthmetal phenate and Zinc dialkyl dithiophosphate containing from 4 to 6carbon atoms in each of the alkyl groups, and from 0.05 to 1.0% byweight of alkanediol containing from 4 to 8 carbon atoms.

3. A lubricating oil composition comprising a major portion of a minerallubricating oil, from 0.1 to 10.0% by weight of oil-soluble copolymer of(A) an ester selected from the group consisting of alkyl acrylates andalkylmethacrylates having alkyl groups in the range of 4 to 6 carbonatoms each (B) an ester selected from the group consisting ofalkylacrylates and alkylmethacrylates having alkyl groups in the rangeof 12 to 20 carbon atoms each and (C) vinyl pyrrolidone, said copolymerhaving a molecular weight in the range of 100,000 to 300,000 and saidvinyl pyrrolidone being from about 0.1 to about 35.0% by Weight of thecopolymer, from 5 to 100 millimoles per kilogram each of neutral calciumpetroleum sulfonate, sulfurized calcium tetradecylphenate and zinc butylhexyl dithiophosphate and from 0.05 to 1.0% by weight of2-methyl-2,4-pentanediol.

4. A lubricating oil composition comprising a major portion of a minerallubricating oil, from 0.1 to 10.0% by weight of oil-soluble copolymer of(A) an ester selected from the group consisting of alkylacrylates andalkylmethacrylates having alkyl groups containing from 4 to 6 carbonatoms each, (B) an ester selected from the group consisting ofalkylacrylates and alkylmethacrylates having alkyl groups containingfrom 12 to 20 carbon atoms each and (C) vinyl pyrrolidone, saidcopolymer having a molecular weight in the range of 100,000 to 300,000and said vinyl pyrrolidone being from about 0.1 to about 35.0% by weightof the copolymer, from 5 to millimoles per kilogram each of neutralcalcium petroleum sulfonate, sulfurized calcium tetradecylphenate andzinc butyl hexyl dithiophosphate and from 0.05 to 1.0% by weight of2-ethyl-1,3-hexanediol.

5. A lubricating oil composition comprising a major portion of a minerallubricating oil, from 0.1 to 10.0% by weight of oil-soluble copolymer of(A) an ester selected from the group consisting of alkylacrylates andalkylmethacrylates having alkyl groups containing from 4 to 6 carbonatoms each, (B) an ester selected from the group consisting ofalkylacrylates and alkylmethacrylates having alkyl groups containingfrom 12 to 20 carbon atoms each and (C) vinyl pyrrolidone, saidcopolymer having a molecular weight in the range of 100,000 to 300,000and said vinyl pyrrolidone being from about 0.1 to about 35.0% by weightof the copolymer, from 5 to 100 millimoles per kilogram of neutralcalcium petroleum sulfonate and from 0.05 to 1.0% by weight of2-ethyl-1,3-hexanedio1.

6. A lubricating oil composition comprising a major portion of a minerallubricating oil, from 0.1 to 10.0% by weight of oil-soluble copolymer of(A) an ester selected from the group consisting of alkylacrylates andalkylmethacrylates having alkyl groups containing from 4 to 6 carbonatoms each, (B) an ester selected from the group consisting ofalkylacrylates and alkylmethacrylates having alkyl groups containingfrom 12 to 20 carbon atoms each and (C) vinyl pyrrolidone, saidcopolymer having a molecular weight in the range of 100,000 to 300,000and said vinyl pyrrolidone being from about 0.1 to about 35.0% by weightof the copolymer, from 5 to 100 millimoles per kilogram of sulfurizedcalcium tetradecyl phenate and from 0.05 to 1.0% by weight of2-ethyl-1,3-hexanediol.

References Cited in the file of this patent UNITED STATES PATENTS2,329,474 Lazar et al. Sept. 14, 1943 2,602,048 Michaels et a1. July 1,1952 2,623,016 Mertes Dec. 23, 1952 2,833,719 Van Horne et al. May 6,1958 2,850,450 Galindo et al. Sept. 2, 1958 2,850,455 Kern et a1. Sept.2, 1958 OTHER REFERENCES Hexylene Glycol, Shell Chem. Corp., SanFrancisco, Calif. 1950, pages 8 and 15. v

1. A MINERAL LUBRICATING OIL COMPOSITION COMPRISING A MAJOR PORTION OF AMINERAL LUBRICATING OIL, FROM 0.1 TO 10.0% BY WEIGHT OF AN OIL-SOLUBLECOPOLYMER OF (A) AN ESTER SELECTED FROM THE GROUP CONSISTING OFALKYLACRYLATES AND ALKYLMETHACRYLATES HAVING ALKYL GROUPS CONTAININGFROM 4 TO 6 CARBON ATOMS EACH, (B) AN ESTER SELECTED FROM THE GROUPCONSISTING OF ALKYLACRYLATES AND ALKYLMETHACRYLATES HAVING ALKYL GROUPSCONTAINING FROM 12 TO 20 CARBON ATOMS EACH AND (C) VINYL PYRROLIDONE,SAID COPOLYMER HAVING A MOLECULAR WEIGHT IN THE RANGE OF 100,000 TO300,000 AND SAID VINYL PYRROLIDONE BEING FROM ABOUT 0.1 TO ABOUT 35.0%BY WEIGHT OF THE COPOLYMER, FROM 5 TO 100 MILLIMOLES PER KILOGRAM OF AMETAL SALT ORGANIC DETERGENT ADDITIVE SELECTED FROM THE CLASS CONSISTINGOF NEUTRAL ALKALINE EARTH METAL PETROLEUM SULFONATE, ALKALINE EARTHMETAL PHENATE, SULFURIZED ALKALINE EARTH METAL PHENATE AND ZINC AROMATICDITHIOPHOSPHATE IN WHICH THE AROMATIC GROUPS ARE SELECTED FROM THE CLASSCONSISTING OF ALKYL PHENYL AND ALKYL NAPHTHYL GROUPS AND FROM 0.05 TO1.0% BY WEIGHT OF ALKANEDIOL CONTAINING FROM 4 TO 8 CARBON ATOMS.